Carcinoembryonic antigen (CEA)
Test Background CEA is a tumour-associated cell surface glycoprotein of 200 kDa normally expressed in embryonic and fetal gut tissues. It can be elevated in almost any advanced adenocarcinoma including breast, prostate, liver, gastric, lung, pancreatic or ovarian cancer, but has greatest usefulness in colorectal carcinoma. It is rarely elevated early in malignancies. Benign conditions in which a raised CEA may be observed include: hepatitis, cirrhosis, alcoholic liver disease, inflammatory bowel disease (Crohn’s and ulcerative colitis), pancreatitis, bronchitis, emphysema and renal disease. It may also be elevated in heavy smokers.
Clinical Indications Colorectal cancer
- Diagnosis: due to low clinical sensitivity CEA is not recommended for screening. It may aid diagnosis in high risk groups as an adjunctive test.
- Prognosis and staging: pre-operative CEA measurement provides prognostic information and can be used in combination with other factors in planning treatment. Raised levels should be evaluated for the presence of distant metastases.
- Treatment monitoring: CEA should be measured at the start of treatment for metastatic disease and every 1-3 months during treatment. Increasing concentrations suggest progressive disease.
- Surveillance: in asymptomatic patients CEA is the most frequent indicator of recurrence. Measurement of CEA is recommended every 3 months in patients with stage II/III disease for at least 3 years following diagnosis.
May be useful in other gastrointestinal malignancies as a general purpose marker for adenocarcinomas, especially for treatment monitoring and surveillance following treatment.
Reference Range ≤5 μg/L
Sample Required SST (gold top) preferred, serum (red top) accepted
Sample Volume 0.5 mL
Turnaround Time 4 days
Notes Abbott Architect assay